1. Field
The present disclosure relates to a dryness sensing circuit and a dryness sensing method.
2. Background
Typically, a clothes dryer is a device for automatically drying clothes in a wet state after washing and a kind thereof may be largely divided into a vented clothes dryer and a condensing clothes dryer.
Between them, a configuration of a vented clothes dryer is described as follows.
FIG. 1 illustrates a structure of a typical vented clothes dryer, and FIG. 2 illustrates a Euro structure of the dryer of FIG. 1. The existing clothes dryer includes a main body 1 having a door 2 formed in a front surface, a drum 3 rotatably installed inside the main body 1 and having a plurality of protruding lifters 4 in an inner circumferential surface, a driving means for granting torque to the drum 3, a heater 5 heating intake external air to a high temperature to generate hot wind, an intake duct 7 communicated with a rear side opening of the drum 3 and guiding the hot wind generated by the heater 5 inside he drum 3, a lint duct 8 communicated with a front opening of the drum 3 and guiding humid air emitted after drying to an exhaust duct 15, and a blower fan 13 installed at a rear side of the lint duct 8 and generating a blower force.
A filter 14 is installed at an inlet part of the lint duct 8, which filters foreign materials such as dust or lint from air emitted from the drum 3.
The driving means for rotating the drum 3 includes a motor 10 and a driving belt 12 connected to a driving pulley 11 coupled to the motor 10 and winding an outer circumference of the drum 3, and rotates the drum 3 according to rotation of the driving belt 12 wound around the driving pulley 11, when the driving pulley 11 rotates due to rotation of the motor 10.
Furthermore, an electrode sensor 30 is installed at the front side of the drum 3 in order to detect a dryness degree of dry target. The electrode sensor 30 includes two metal plates in parallel. When a dry target simultaneously contacts both metal plates, the electrode sensor 30 senses a dryness degree of clothes by using impedance generated both end of the electrode according to moisture containment of the dry target, and outputs the sensed result as a voltage signal. In addition, the dryness degree may be divided into a plurality of level (for example, very dry, more dry, normal, less dry, damp dry) according to the moisture containment. In this case, in the very level and the damp level, since a variation amount of the voltage signal is not great, which corresponds to a change of the impedance differed according to a change of the moisture containment of the dry target at both ends of the electrode, it is difficult to accurately measure the dryness degree of the dry target.